The World of Comets

according action amongst ancients aphelion apparition Arago astronomers atmosphere believe Biela's comet bolides bright bright bands brilliant calculated cause celestial bodies centre century comet appeared cometary orbits cometary tails curve described diameter direction discovered diurnal motion Donati's comet earth eccentricity elliptic orbit Encke Encke's comet Ephorus epoch equal fact Faye gravitation Halley Halley's comet heavens hyperbolic hypothesis inclination Jupiter Kepler Lalande law of Kepler laws less light longitude luminous major axis mass matter mean distance meteors moon motion move movement Myndus nearly nebulosity Newton node nucleus number of comets observed opinion parabolic elements parabolic orbit perihelion distance perihelion passage periodical comets perturbations phenomena Pingré planetary planets position prediction presage radius vector rays regarded region remarkable repulsive force retrograde revolution SECTION seen Seneca solar system space spectrum stars suppose telescope theory tion true velocity visible Winnecke Yvon Villarceau